Boy, do I know hydraulic suspension now. I just replaced every single part with the exception of the lines and the hydraulic control valve in the back. There is no other filter except in the reservoir. When replacing fluid, you need to disconnect the rod at the back held on with a 10mm nut and move it down to lower suspension to change whats in the accumulators then back up once clean and reattach. I would have someone there to replenish the fluid cause it does move somewhat quickley. Hope this helps!